A two-wire transmitter starter circuit is configured to stably supply power at the time of start-up. The two-wire transmitter starter circuit includes a starter current generation circuit. The starter current generation circuit is connected in parallel with a current conversion unit configured to convert a detection signal of a sensor to a predetermined DC current. The starter current generation circuit includes a first series circuit where a first resistor and a shunt regulator are connected in series, and a second series circuit where a switching element and a second resistor are connected in series. The shunt regulator includes a first control terminal connected to a connection point of the switching element and the second resistor. The switching element includes a second control terminal connected to a connection point of the first resistor and the shunt regulator.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A two-wire transmitter starter circuit which is configured to stably supply power at the time of start-up, the two-wire transmitter starter circuit comprising a starter current generation circuit, the starter current generation circuit being connected in parallel with a current conversion unit configured to convert a detection signal of a sensor to a predetermined DC current, wherein the starter current generation circuit comprises a first series circuit where a first resistor and a shunt regulator are connected in series, and a second series circuit where a switching element and a second resistor are connected in series, wherein the shunt regulator comprises a first control terminal connected to a connection point of the switching element and the second resistor, and wherein the switching element comprises a second control terminal connected to a connection point of the first resistor and the shunt regulator.
2. The two-wire transmitter starter circuit according to claim 1 , wherein the switching element is a field effect transistor.
3. The two-wire transmitter starter circuit according to claim 1 , wherein the switching element is a junction transistor.
4. The two-wire transmitter starter circuit according to claim 1 , wherein the first series circuit and the second series circuit are connected in parallel to each other.
5. The two-wire transmitter starter circuit according to claim 1 , wherein the shunt regulator is configured to control the second control terminal to apply across the second resistor the same voltage as a reference voltage in the shunt regulator.
6. A two-wire transmitter comprising: a two-wire transmitter starter circuit configured to stably supply power at the time of start-up, the two-wire transmitter starter circuit comprising a starter current generation circuit; and a current conversion unit configured to convert a detection signal of a sensor to a predetermined DC current, wherein the starter current generation circuit and the current conversion unit are connected in parallel to each other, wherein the starter current generation circuit comprises a first series circuit where a first resistor and a shunt regulator are connected in series, and a second series circuit where a switching element and a second resistor are connected in series, wherein the shunt regulator comprises a first control terminal connected to a connection point of the switching element and the second resistor, and wherein the switching element comprises a second control terminal connected to a connection point of the first resistor and the shunt regulator.
7. The two-wire transmitter according to claim 6 , wherein the switching element is a field effect transistor.
8. The two-wire transmitter according to claim 6 , wherein the switching element is a junction transistor.
9. The two-wire transmitter according to claim 6 , wherein the current conversion unit comprises two transmission lines configuring a two-wire type transmission line, and wherein a third resistor is connected to one of the two transmission lines, and the third resistor is configured to detect current flowing through the transmission line.
10. The two-wire transmitter according to claim 6 , wherein the first series circuit and the second series circuit are connected in parallel to each other.
11. The two-wire transmitter according to claim 6 , wherein the shunt regulator is configured to control the second control terminal to apply across the second resistor the same voltage as a reference voltage in the shunt regulator.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
November 12, 2013
December 15, 2015
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